Photochemical reduction of UO22+ in the presence of alcohol studied by DFT calculations


Photochemical reduction of UO22+ in the presence of alcohol studied by DFT calculations

Tsushima, S.

A well-known photochemical process of UVIO2 2+ reduction to UVO2 + in the presence of alcohols was studied by density functional theory (DFT) calculations. It was found that the first process which takes place is a photoexcitation of the ground-state UO2 2+ to the triplet excited state (*UO2 2+) followed by a significant shortening of the *UO2 2+-to-alcohol Oax-H distance. A charge transfer from *UO2 2+ to alcohol and hydrogen abstraction takes place in the following step. Consequently, UVIO2 2+ gets reduced to UVO(OH)2+. The photochemical byproduct RC·HOH acts further as a reducing agent toward UO2 2+ to yield UO2 + and RCHO (aldehyde). Only a combination of these two reactions can explain a high quantum yield of this reaction. In the absence of alcohol, the lowest-lying triplet state exhibits a different character, and photoreduction is unlikely to take place via the same mechanism. The present results agree well with recent experimental finding [J. Am. Chem. Soc. 2006, 128, 14024] and supports the idea that the Oax-H linkage between UO2 2+ and the solvent molecule is the key to the photochemical reduction process.

  • Inorganic Chemistry 48(2009)11, 4856-4862
  • Lecture (Conference)
    ROBL-Radiochemie Workshop, 18.12.2008, Dresden, Germany

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Publ.-Id: 12143